1,721,000 research outputs found
Pigment diversity in freshwater phytoplankton. II. Summer‐succession in three Dutch lakes with different trophic characteristics
No full textTAXONOMY AND MORPHOLOGY OF THE MARINE PLANKTON DIATOMS<i>THALASSIONEMA</i>AND<i>THALASSIOTHRIX</i>
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6. Harmful marine algal blooms and climate change: progress on a formidable predictive challenge
No full textOBSERVATIONS ON THE MUCILAGINOUS DIATOM<i>THALASSIOSIRA BIPARTITA</i>(RATTRAY) COMB. NOV. FROM THE TROPICAL INDO-WEST PACIFIC
No full textTransport of harmful marine microalgae via ship's ballast water: Management and mitigation with special reference to the Arabian Gulf region
No full textThe potential for transport of non-indigenous marine microalgae via ship's ballast water has been amply demonstrated, and nearly all known harmful algal bloom species have been documented in viable form from ship's ballast water. Ballast water uptake needs to be strongly discouraged during harmful algal bloom events. Efficacy of ballast water exchange in removing harmful microalgal cells is limited, since this nearly always leaves behind a viable inoculum. The precise location of ballast water exchange needs to be carefully chosen, and retention of dinoflagellate cysts and diatom spores in ballast tank sediments is of special concern. The only fully effective ballast water treatment for microalgae is the application of biocides, but heat treatment also offers considerable promise especially in subtropical and tropical waters. To manage harmful algal blooms, other key environmental drivers such as eutrophication and climate change also need to be addressed. Effective monitoring for harmful algal species and their toxins remains the critical tool to protect human health, fisheries, aquaculture and desalination industries. Challenges and opportunities for ballast water management in the Arabian Gulf region are discussed.</jats:p
6 Harmful marine algal blooms and climate change: progress on a formidable predictive challenge
No full textAn optimized method for the extraction of ancient eukaryote DNA from marine sediments
No full textMarine sedimentary ancient DNA (sedaDNA) provides a powerful means to reconstruct marine palaeo-communities across the food web. However, currently there are few optimized sedaDNA extraction protocols available to maximize the yield of small DNA fragments typical of ancient DNA (aDNA) across a broad diversity of eukaryotes. We compared seven combinations of sedaDNA extraction treatments and sequencing library preparations using marine sediments collected at a water depth of 104 m off Maria Island, Tasmania, in 2018. These seven methods contrasted frozen versus refrigerated sediment, bead-beating induced cell lysis versus ethylenediaminetetraacetic acid (EDTA) incubation, DNA binding in silica spin columns versus in silica-solution, diluted versus undiluted DNA in shotgun library preparations to test potential inhibition issues during amplification steps, and size-selection of low molecular-weight (LMW) DNA to increase the extraction efficiency of sedaDNA. Maximum efficiency was obtained from frozen sediments subjected to a combination of EDTA incubation and bead-beating, DNA binding in silica-solution, and undiluted DNA in shotgun libraries, across 45 marine eukaryotic taxa. We present an optimized extraction protocol integrating these steps, with an optional post-library LMW size-selection step to retain DNA fragments of ≤500 base pairs. We also describe a stringent bioinformatic filtering approach for metagenomic data and provide a comprehensive list of contaminants as a reference for future sedaDNA studies. The new extraction and data-processing protocol should improve quantitative paleo-monitoring of eukaryotes from marine sediments, as well as other studies relying on the detection of highly fragmented and degraded eukaryote DNA in sediments.Linda Armbrecht, Salvador Herrando-Pérez, Raphael Eisenhofer, Gustaaf M. Hallegraeff, Christopher J. S. Bolch, Alan Coope
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